Evaluation of the antioxidant enzyme activity level in patients with alopecia areata

Alopecia areata (AA) is a disease with complex and not fully known etiopathogenesis, associated with hair follicle damage [1]. The disease affects only hair containing melanin, therefore grey streaks remain in the foci of alopecia. It happens that after 3 to 6 months there is spontaneous regrowth – new hair is then free of dye and their repeat pigmentation occurs only after a few weeks [2].
One of the theories that elucidates the pathomechanism of AA is the theory of oxidative stress [3]. The proof of the validity of this theory can be the presence of new grey hair in patients with AA. The study has shown that millimolar concentrations of hydrogen peroxide (H₂O2) are accumulated within grey hair [4]. Its presence inhibits the conversion of tyrosine into melanin by inactivation of the enzyme tyrosinase. The increase in the level of H₂O2 is most probably due to a decrease in activity of catalase (CAT) responsible for its detoxification [5].
H₂O2 decomposition is assumed to occur mainly with the participation of glutathione peroxidase (GPx), thus CAT acts only as an auxiliary and is active when extremely high concentrations of H₂O2 occur [6]. In turn, the biological role of superoxide dismutase (SOD) is to catalyse reactions of dismutation of superoxide radicals with simultaneous generation of H₂O2 [7]. In physiological conditions these enzymes operate together; for this reason, the inactivation of any of these enzymes will weaken the antioxidant defence of the body.
The objective of this study was to evaluate the state of oxidant-antioxidant balance in patients with AA by assessment of the most important antioxidant enzymes, GPx, CAT and SOD, in patients with AA. The study included 30 AA patients (23 females/8 males, mean age: 34.4 ±10.9) and the control group consisting of 30 age- and sex-matched healthy volunteers (17 females/13 males, mean age: 37.3 ±17.4). There was no significant difference between groups with regard to age and body mass index (BMI).
A disturbance in the oxidative-antioxidant balance was demonstrated by a statistically significant decrease in the GPx activity level in blood erythrocytes samples from the patients with AA as compared to the control group (p = 0.001). Also a decrease in CAT activity was noted in patients with AA as compared to the control group, but these differences were not statistically significant (p = 0.491). A slight, statistically...


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